1. Field of the Invention
The present invention relates to a fault diagnosis device for a multiplexer.
2. Description of Related Art
Japanese Patent No. 4801180 describes a fault diagnosis device for a multiplexer including a plurality of switches operated to select one of a plurality of input channels to be connected to an output channel. This fault diagnosis device is configured to diagnose whether the multiplexer is faulty or not by monitoring the voltage appearing at the output channel of the multiplexer when different test voltages are successively applied to the plurality of the input channels of the multiplexer.
The fault diagnosis device makes it possible to reliably determine whether the multiplexer is faulty or not. However, the fault diagnosis device has to be provided with a structure for applying the different test voltages to the respective input channels. Accordingly, since the circuit scale of the fault diagnosis device is large, the manufacturing cost thereof is large.